Looking for William Henry Chester Who was Supposed to Have Been Born IN Ramsgate Kent UK About 1854 1855 He Married Annie Louisa Campbell IN Sydney...

They had 10 children. He died in 1920. On his marriage certificate, William's parents were Thomas Chester and Sarah Fontains/Fontaine? I can't find a marriage for them in the UK and can't find a William Henry with parents Thomas and Sarah of the right age/location. Also can't find him in the shipping indexes to New South Wales, although there is one who went from New Zealand to Victoria with appropriate age and date. No one knows or can remember whether he had siblings and those who would have known have died. His past is a real mystery in my family. I hope someone can help.